A Sodium-Cooled Fast Reactor (SFR) is a type of nuclear reactor that uses liquid sodium as a coolant. This design allows for efficient heat transfer and enables the reactor to operate at high temperatures. SFRs utilize fast neutrons to sustain the nuclear fission process, which can improve fuel efficiency and reduce nuclear waste. SFRs are part of the broader category of fast reactors, which can recycle nuclear fuel and potentially use a variety of fuel types, including plutonium and uranium. This technology is being explored for its potential to enhance the sustainability of nuclear energy and reduce reliance on traditional reactors.